From what little I could find, I believe you were the engineer on the Mary Hopkin session for "Goodbye". At the time (1969), being a young engineer at 16, and studying Beatle recordings, this song sounded a bit different than what I had been hearing from the Beatles, yet similar in musical/arrangement ways (maybe the McCartney influence). It's wonderful recording.

Could you share any information on how you approached sessions that the Beatles had been producing for others, or this "Googbye" session in particular?

As far as Beatles producing other acts, one looked at them exactly the same as one did an actual Beatles session. As with any session you were there to give the best you could. The Beatles, either as artist or producer, certainly weren't treated any differently than any other act.